Goals of this research are to study (or reconstruct) quantitatively the structures of the neuronal networks in three widely different specimens (nematodes neuronal network, vertebrate and invertebrate visual systems) and to correlate each reconstructed structure with its specific function. As such this is a quantitative analysis incorporating synthesis of neuron networks in the structural and functional domains. The reconstruction at the EM level will be carried out by interactively tracing the contour of a given neuron (plain or Golgi-impregnated) from electron micrographs of serial sections and by recording the coordinates of the traced contour. The contour for each section will be aligned with respect to one another; "stacked up" in the computer, the tracings will be computed to form a D3 picture of an entire neuron. At the level of light microscopy Golgi-impregnated or Procion-dye injected neurons will be sectioned optically at 10 to 20 levels and digitized images will be stored in the computer memory for later processing. Such processing includes edge-enhancement and out-of-focus image subtraction. The final results will be viewed as a stereopair which can be rotated to any angle for ease of interpretation.